With sirens blaring, horns honking and joyful cheers, teachers and the principal of T.C. Williams High School in Alexandria, Va., surprised 28 seniors on May 2. (Video: Jessica Contrera/The Washington Post)

Lights flashed, and a siren blared as the sheriff’s SUV pulled into an apartment complex Saturday afternoon. Neighbors opened their blinds to see what was about to happen. An apprehensive teenager emerged from her apartment.

“This must be her,” said a voice over the sheriff’s megaphone. “Come on out, Miss Alex Espinoza.”

Espinoza could see cars everywhere, covered in streamers and window paint. She could hear people clapping and cheering. Then, one of her favorite teachers ran up to her, and with a mask on, presented her with an envelope.

Inside was the stole that Espinoza, a senior at T.C. Williams High School, would have worn at graduation to show she had completed an Advanced Placement Capstone. For the 28 students in the two-year program, which involves a 25- to 50-page thesis project, there was supposed to be a cake-filled celebration so students could present their research to the community.

Now, it was just another milestone missed, a reminder of the prom dresses that had to be returned, the college T-shirt day that came and went, the walk across the graduation stage that will never come.

Or it would have been, if teacher Sarah Kiyak had been able to sleep. Since she and her students stopped going to school March 13, Kiyak has found herself awake at all hours, thinking, overthinking and then plotting.

She looked up all of her capstone students’ addresses on Google Maps and made a route for a makeshift parade. When other teachers found out what she was planning, they asked to join. An administrator’s husband, a detective, borrowed the sheriff’s vehicle. Parents were contacted, and when one of the parents mentioned the celebration to Alexandria Mayor Justin Wilson (D), he asked to come, too.

“Yesterday, we announced three more deaths [from covid-19]. We have 26 deaths in the city. Every day, it’s another shoe falling. But this, this is something so positive,” Wilson said.

He beeped and waved each time the caravan of a dozen cars pulled onto tree-lined streets and apartment building parking lots. Students emerged from their homes with sweatpants on and jaws hanging open, a sign that their classmates hadn’t texted and ruined the surprise for each other. They had spent the past few weeks putting final edits on their theses, which studied topics that included the elimination of rape culture, perceptions of bisexuality, climate change in science curriculums and the school-to-prison pipeline.

Senior Kelly Jones was inspired by the book “White Fragility” to research her classmates’ comfort level in talking about race. She never got to present her findings.

“I was just upstairs reading,” she said Saturday, “when [my sister] came in and said, ‘There’s something weird happening in the street.’ ”

Her sister took her arm and dragged her into the front yard. For Jones, who is blind, so much of high school was about ensuring that she had the same experiences as other students. She used a high-powered camera to magnify text, but she wouldn’t bring her cane to school. She figured most students who didn’t know her well didn’t know about her disability. Now, so many of the “normal” parts of high school were gone for all of her classmates.

When Jones heard people cheering her name, she clapped, too. Her parents pulled out their phones and started taking pictures. Neighbors came outside to watch.

“And Kelly is headed to . . . Columbia!” the administrator on the megaphone told the neighborhood.

The mayor and the principal waved. Her parents took more pictures.

“Isn’t that fantastic?” one of her neighbors said.

It took nearly five hours for the parade to make it to all 28 students. Some looked embarrassed. Some started to cry.

Kiyak went home to get some sleep, proud that she had given her students a moment to remember and a chance to celebrate all they had to look forward to. Come the fall, they would be college-bound.

“I just hope,” she said, “that they are actually able to go.”